Compression refrigerating machine



G. FERGUSON.

COMPRESSION REFRIGERATFNG MACHINE.

APPLICATION FILED NOV. 8; 1918.

mural) STATES PATENT oer-" ce.

GEORGE FERGUSON, F APELDOORN, NETHERLANDS, ASSIGNOR TO MAGHINEFAIBRIEK EN DGORN, NETHERLANDS, THE KINGDOM OF THE NETHERLANDS.

APnLDooRNsoHE or APEL;

COMPRESSION .REFBIGERATING MACHINE.

' To all whom it may concern:

Be it known that l, GEORGE FERoUsoN, a subject of the Queen of the Netherlands, residing at Apeldoorn, Province of Gelderat land, in the Kingdom of the Netherlands,

have invented certain new and useful improvements in Compression Refrigerating Machines, of which the following is a specification.

The invention relates 'to a compressing cylinder device for refrigerating machines, working with two evaporating pressures.

With ordinary compressors, gas of a certain pressure is admitted into the cylinder during the suction stroke; with refrigerating machines, working with two evaporating pressures, two functions during the suction stroke, namely first the low pressure gas and afterwards the high 90 pressure gas must be brought into the cylinder. For these two about the same course of time is available as is the case for the inlet of the gas into a compressing cylinder, working with one single 2 evaporating pressure. lit will-therefore be necessary to perform the inlet of gases of two difierent evaporating pressures in such a manner, that the gas of one pressure does not influence the admission of the other gas W in an unfavourable way; the current which may be favourable for one gas disadvantageous influence upon the other gas.

The present invention relates to a compressing cylinder for refrigerating machines, working with two evaporating pressures, with which cylinder a favourable inlet for both gases is obtained.

With the special construction of the compressing cylinder, mentioned above, the

may exert a the inlet of temperature of the cylinder is influenced in a favourable way, as this special construction can be compared with the water jacket of a compressor, working with superheating. 46 With the present invention the working part of the cylinder is enclosed entirely or nearly entirely by a jacket, which by a ring of small apertures gives access for the high pressure vapours into the cylinder. These 50 apertures are opened during the last part of the suction stroke by the piston, and are so formed, that their section becomes gradually narrower in the direction from the such apertures to a must be performed functions together only Specification of Letters Patent. t t 21, 1922, Application filed November s, 1918. Serial No. 261,643.

jacket into the cylinder. In the same way the jacket is connected to the high pressure pipe by an opening which grows wider in the direction of the jacket.

' On compressing cylinders similar tures for the inlet, of which the section increases progressively, are not novel; the novel feature however is the application of compressing cylinder, working with two evaporating pressures, thus obtaining a favourable inlet cylinder of both the low pressure and the high pressure vapours.

With ordinary compressing cylinders, the suction into the cylinder begins at the beginning of the suction stroke, and is con tinned even during the first part of the compression stroke. The slow closing of the suction valve has the-consequence, that during the low speeds of dead center, gas can enter into the cylinder.

When the end of the piston stroke, as

the case with the present arrangement, is used for the admission of the high pressure gas, this not only decreases the efficiency of the suction stroke to fill the cylinder with low pressure gas, but especially eliminates that part of the stroke during which the high pressure gas is admitted; on account of the low piston speed, the cylinder is filled with gas, which under ordinary arrangements would not enter the cylinder on account of the great velocity of the piston.

In order to insure the cylinders being filled as much as possible with low pressure gas, the cylinder is provided with a large number of circumferential apertures through which the high pressure gas enters. By this means, nearly the whole suction stroke is first used to fill the whole cylinder with low pressure vapours, which, vapors can enter into the cylinder, when the piston moves at low speed also. The small size of the apertures for the admission of the high pressure vapours, givinga long period of admission for the pressure gas, results of course in a much shorter period of admissionof the high pressure vapours. The admission of these high pressure vapours,

the cylinder as soon as the piston o ens the apertures (the suction valve throug which the low pressure vapours enter, being closed into the low enterlng as theydo into aperthe piston near the end of the entire working part of the cylinder, this receiver also acts as a cooling jacket.

The invention is illustrated and explained bythe accompanying drawing, in which Fig. 1 represents a complete refrigerating plant according to the present invention, working with two evaporating pressures in a single compressing cylinder which in the present case is a single acting vertical machine and in which the suction valve is arranged in the piston.

Fig.2 is on a; larger scale a vertical sec- 1 tion through the apertures for the inlet of the high pressure vapours into the cylinder and Fig. 3 is a front view of these apertures.

1 is a regulating cock, used with compression chines. Through this cook the circulating liquid streams from a condenser, which is not shown in the drawing, to the high pressure evaporating coil 2. In'this high pressure evaporator heat is absorbed at high temperature, thus evaporating a part of the liquid therein, so that after passingthe high pressure evaporator there is a mixture of gas and liquid. This mixture is led to the liquid separatorB, which eventually forms part of the high pressure evaporator. From this separator the high pressure gas is sucked off by the compressor through a pipe 4 in a way, which will afterwards be explained. The'liquid collects at the bottom of the seprefrigerating maarator and is discharged through a float-device 5 to the low pressure evaporator 7.-

The liquid which is discharged into the low pressure evaporator 7, is evaporated therein at a low pressure so that in this low pressure evaporator heat is absorbed at a low temperature. From .there the develo ed vapours are led in the usual way throug a pipe 8 to the suction opening 9 of the compressor which is adapted to communicate with the-working part of the compression cylinder as hereinafter described.

The drawing gives a vertical single acting compressing cylinder 11, intowhich the vapours developed in the evaporators are sucked by a hollow piston 10, which is provided at one side witha lateral opening or 'port 10' and at the top is provided with a suction valve 12. The high pressure vapours enter to the presin Figures 2 as it is generallythe receiver, this into the cylinder as soon as the piston 10 sure in the cylinder (on account of the ML mission of the high pressure vapours through the apertures 13) closes the suction valve 12. ese apertures 13, which in axial direction of the cylinder are of small size, are arranged in a large number around the entire circumference of the cylinder. It will be preferable to give them a shape as depicted and 3 so that these apertures have a circular shape '14 at the inner side of the cylinder and at the outer side of the cylinder increase in axial direction toan oblong shape 15. With this shape of the apex tures, the material of the cylinder practical] is not weakened and the casting of the c l inder is influenced in a favourable way to the core of the jacket, than would be possible with small cores of constant circular section.

More important however is the form of these apertures for the admission of the high pressure vapours into a cylinder. In the receiver 16, which is provided with these apertures 13 and which encloses the cylinder all around, the high pressure vapours enter from the evaporator through pipe 4 and opening 17, which enlarges in a conical form in the direction of the receiver. This re ceiver enables the gas to flow uniformly through all the In the receiver, the velocity-of the gas is naturally much less than in the apertures 13 and the pipe 4; therefore between pipe 4 and the cylinder the current of gas is first retarded and then accelerated.

. Each transformation of pressure and of pressure into velocity is accompanied by losses caused by friction, which result in the production of useless or disadvantageous heat, instead of useful energy. This is of great importance, especially when, as in the present case, high velocities must be obtained during a short period of admission. These losses. are the greatest, when these transformations are performed with interruptions. With the form of the apertures 13 and the opening 17, growing gradually larger in the direction of transformation of energy velocity into lit) misses is performed more adually, thus decreasing the losses cause by friction and therefore obtaining a more perfect and m id inlet of the high pressure gases into t e cylinder. Y

With the lip-stroke of the piston, first the apertures 13 are shut ofi, the low pressure and high pressure vapours to ether are comressed and then discharged through a valve in the cylinder cover (not shown).

The jacket or receiver 16 ofthe cylinder extends nearly over the whole working part of the cylinder. The high pressure vapours therefore act as a cooling medium on this part of the cylinder, which is heated by the heat of compression; thus this receiver serves the same purpose as a water jacket.

The same jacket and a ertures of admission, as described here a ove, can also be applied to single acting compressin cylinders, in Whichthe suttion-valve is p aced in the cylinder-cover, or to double-acting cylinders, in which one or more suction-valves are arranged at each end of the cylinder,

l ihat li claim is: 1. in a gas compressor for refrigerating systems working with two intake pressures, in combination, a cylinder, a hollow piston fitting within said cylinder having a lateral opening and an opening controlled by a pressure actuated valve, a jacket substantially enclosing the working part of said cyl inder and forming a receiver for high pressure gas, a plurality of apertures formed in said cylinder adapted to be uncovered by said piston when approaching the end of the gas into the cylinder,

7 within said cylinder,

being opened during the last suction stroke for admitting high pressure a low pressure gas receiving chamber in communication with said cylinder through said lateral and valve controlled openings, whereb low pressure gas is admitted to said cylin er during the suction stroke of the piston until said apertures are uncovered and high pressure gas is admitted in quantities sufiicient to exert pressure on said valve and close the same, the high pressure gas in said jacket acting as a cooling medium for the working part of the cylinder. I

2. In a gas compressor for refrigerating systems working with two intake pressures, incomhination, a cylinder, a piston fitting a jacket substantially enclosing the working part of said cylinder and forming a receiver for high pressure gas, a plurality of apertures formed in said cylinder for theadmission of the high pressure gas into the cylinder, ing so formed that I ually wider in the direction of the jacket and art of each suction stroke of the piston, and a pipe connecting said jacket with a high pressure chamber through 'an opening in said jacket the section of which becomes gradually wider in the direction of the jacket.

In testimony whereof I have hereunto set my hand,

, GEQRGE FERGUSON. Witnesses: c D. Knnirn,

M. ALvARAno.

said apertures hetheir section grows grad- 

